The graph to the left is the discount rate for T-Bills with a 3-month maturity.

Treasury bills are short-term debt securities issued by the U.S. Government. They are issued in lengths of four weeks (30 days), three months (90 days), six months (180 days), and one year (360 days). However, the one year bill is currently no longer issued. Treasury bills are known as a zero coupon, or discount security, since it pays the interest and principal at maturity.

The rates listed on Treasury bills are known as discount rates. However, it is important know two things when purchasing Treasury bills: